Two new sitcoms get tangled in ethnic stereotypes

Keep your earplugs handy. Two ethnic-oriented series premiere this week with only one thing in common other than their ethnicity - loudness.

Although a.k.a. Pablo (ABC, Tuesdays, 8:30-9 p.m., premiering March 6) concerns a Mexican-American family, and Mama Malone (CBS, Wednesdays, 8:30-9 p.m., premiering March 7) concerns an Italian-American family, both shows start out with the highest decibel ratings in the business. All the characters shout at one another as if their mikes had gone dead on the stage of the Radio City Music Hall. And both shows depend upon food stereotypes to carry the day. But are tacos and lasagna really that funny? Ethnic rehash

The best thing about ''Pablo'' is that it marks Norman Lear's return to series comedy after a sojourn in the wilds of national politics and movies.

As creator, executive producer, and co-writer of the premiere episode, Mr. Lear carries with him a wealth of 1970s sitcom experience. Perhaps too much. ''Pablo'' is a mildly disconcerting throwback to 1970s situation comedy with deeper roots in the L.A. Comedy Store than in the L.A. barrio. Ethnic humor has gone several steps beyond the running comic routine in the series: ''When I travel, people don't know who I am. That's why I always carry my Mexican Express card'' (a street fighter's knife is shown between the teeth). It seems to have taken a whole corps of Hispanic actors and consultants to approve that little gag.

''Pablo'' is basically a Freddie Prinze show, without Freddie Prinze. Paul Rodriguez as Pablo Rivera just doesn't have the mischievous fire needed to accomplish the mission. Hector Elizondo, as a would-be agent sporting an atrocious new wig, is a fine comic invention. The big surprise for me was Katy Jurado believably portraying a ghetto mother rather than the glamorous Mexican beauty she has usually played.

I sampled the fourth episode of ''Pablo'' as well as the premiere and found it still relied on standard ethnic humor: Substitute blacks or Jews or Vietnamese for the Mexican-Americans and there would not be much difference - except for the taco jokes (white Americans are called ''bread-eaters'').

Bear in mind that it took Lear's ''All in the Family'' and ''One Day at a Time'' several months before they finally hit their stride. With Norman Lear at the helm, I'm still hoping for ''Pablo'' to use the barrio as a 1980s launching pad rather than a 1970s wallowing pond. Life as TV

We've all talked about it. Finally it has arrived. Life doesn't just seem to be a TV show, it is a TV show.

''Mama Malone'' has taken that one last step that erases the line between comic reality and electronic fantasy. It is life as a TV show.

''Mama'' all takes place in Mama's kitchen in Brooklyn, where her television show, ''Cooking With Mama Leone,'' is being taped. Lila Kaye, a sort of de-Latinized Italian, deals with her family problems on camera as her grandson, daughter, brother, ancient parish priest, and his Puerto Rican assistant meander into the kitchen. When there is a complaint that somebody took a shower when the lasagna dough had been hung up to dry, Mama insists, ''Recipes I can give you; brains I can't.'' A response worthy of Mollie Goldberg or any ethnic comedienne you can name. Is that Italian?

So, while ''Mama Malone'' starts with a rather amusing concept, and ''a.k.a. Pablo'' boasts excellent production credentials, both of them bog down in interchangeable ethnic humor. Just as a bagel alone doesn't make for acceptable Jewish humor or black-eyed peas alone make for good black humor, so neither tacos nor lasagna alone makes for acceptable Mexican-American and Italian-American humor. A sitcom marches on more than its stomach.

There's got to be more to ethnic comedy than shouting and tumult and food. Both new shows must be given high grades for at least trying to rescue TV situation comedy from its status in the racial doldrums. Now, good writers need to rescue it from the neighborhood deli.